Refactor: Extract root components architecture with comprehensive tests

src/RootComponents/LoadingExplorer.test.tsx

@@ -0,0 +1,71 @@
+import "@testing-library/jest-dom";
+import { render, screen } from "@testing-library/react";
+import React from "react";
+import LoadingExplorer from "./LoadingExplorer";
+
+jest.mock("../../images/HdeConnectCosmosDB.svg", () => "test-hde-connect-image.svg");
+
+jest.mock("@fluentui/react-components", () => ({
+  makeStyles: jest.fn(() => () => ({
+    root: "mock-root-class",
+  })),
+}));
+
+describe("LoadingExplorer", () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  test("should render loading explorer component", () => {
+    render(<LoadingExplorer />);
+
+    const container = screen.getByRole("alert");
+    expect(container).toBeInTheDocument();
+    expect(container).toHaveTextContent("Connecting...");
+  });
+
+  test("should display welcome title", () => {
+    render(<LoadingExplorer />);
+
+    const title = screen.getByText("Welcome to Azure Cosmos DB");
+    expect(title).toBeInTheDocument();
+    expect(title).toHaveAttribute("id", "explorerLoadingStatusTitle");
+  });
+
+  test("should display connecting status text", () => {
+    render(<LoadingExplorer />);
+
+    const statusText = screen.getByText("Connecting...");
+    expect(statusText).toBeInTheDocument();
+    expect(statusText).toHaveAttribute("id", "explorerLoadingStatusText");
+    expect(statusText).toHaveAttribute("role", "alert");
+  });
+
+  test("should render Azure Cosmos DB image", () => {
+    render(<LoadingExplorer />);
+
+    const image = screen.getByAltText("Azure Cosmos DB");
+    expect(image).toBeInTheDocument();
+    expect(image).toHaveAttribute("src", "test-hde-connect-image.svg");
+  });
+
+  test("should have correct class structure", () => {
+    render(<LoadingExplorer />);
+
+    const splashContainer = document.querySelector(".splashLoaderContainer");
+    expect(splashContainer).toBeInTheDocument();
+
+    const contentContainer = document.querySelector(".splashLoaderContentContainer");
+    expect(contentContainer).toBeInTheDocument();
+
+    const connectContent = document.querySelector(".connectExplorerContent");
+    expect(connectContent).toBeInTheDocument();
+  });
+
+  test("should apply CSS classes correctly", () => {
+    const { container } = render(<LoadingExplorer />);
+
+    const rootDiv = container.firstChild as HTMLElement;
+    expect(rootDiv).toHaveClass("mock-root-class");
+  });
+});